1. Field of the Invention
The present invention relates to hand held printers, and, more particularly, to a hand held printer with vertical misalignment correction.
2. Description of the Related Art
A hand held printer, also sometimes referred to as a hand-operated printer, is a printer that mounts a printhead and ink supply, which may be in the form of an ink jet printhead cartridge, wherein the printer itself Is moved relative to the print medium, such as a sheet of paper, to position the printhead relative to the print medium. Thus, unlike a typical desktop printer, the hand held printer does not include a drive mechanism for physically positioning the printhead relative to the print medium, nor does a hand held printer include a media feed system for feeding a sheet of print media.
The hand held printer is typically referred to as a single axis (X-axis) printer. The hand held printer has an optical encoder that is used to provide position data for firing the printhead by sensing the relative motion of the hand held printer relative to the print medium. Thus, such a hand held printer is designed to print a single swath having a height corresponding to the height of the printhead. However, since the vertical spacing between the printhead nozzles of the printhead is relatively small, e.g., 0.04 millimeters, it is difficult for a user to manually maintain the hand held printer along a straight path, and a small shift of the hand held printer in the vertical direction can produce a noticeable detect in the printed image, e.g., in the form of a wavy line of text.